The present invention relates to the processing of work pieces used in semiconductor fabrication. More particularly, the present invention relates to a reusable container, or liner, for use in a work piece plasma processing chamber.
A plasma is a collection of electrically charged and neutral particles. In a plasma, the density of negatively-charged particles (electrons and negative ions) is equal to the density of positively-charged particles (positive ions). Plasma generation may be conducted by applying power to electrodes in a chamber of a reactor. In diode or parallel plate reactors, power is applied to one electrode to generate a plasma. In triode reactors, power is typically applied to two of three electrodes to generate a plasma.
In radio frequency (RF) plasma generation, for a diode reactor, a sinusoidal signal is sent to an electrode of a pair of electrodes. Conventionally, a chuck or susceptor is the powered electrode. Examples of parallel plate reactors include the 5000MERIE from Applied Materials, Santa Clara, Calif.
A plasma source material, which typically includes one or more gases, such as, for example, argon, silane (SiH4), oxygen, TEOS, diethylsilane, and silicon tetrafluoride (SiF4), is directed to an interelectrode gap between the pair of electrodes. The amplitude of the RF signal must be sufficiently high for a breakdown of plasma source material. In this manner, electrons have sufficient energy to ionize the plasma source material and to replenish the supply of electrons to sustain a plasma. The ionization potential, the minimum energy needed to remove an electron from an atom or molecule, varies with different atoms or molecules.
In a typical triode reactor, three parallel plates or electrodes are used. The middle or intermediate electrode is conventionally located in between a top and bottom electrode, and thus two interelectrode cavities or regions are defined (one between top and middle electrode and one between middle and bottom electrode). The middle electrode typically has holes in it. Conventionally, both the top and bottom electrode are powered via RF sources, and the middle electrode is grounded. Examples of triode reactors are available from Lam Research, Fremont, Calif., and Tegal Corporation Ltd., San Diego, Calif.
Parallel plate and triode reactors generate capacitively coupled plasmas. These are conventionally xe2x80x9clow densityxe2x80x9d plasmas (ion-electron density of less or equal to 1010 ions-electrons per cm3) as compared with high-density (also known as xe2x80x9chi densityxe2x80x9d) plasmas which are generated by systems such as electron cyclotron resonance (ECR) and inductively coupled plasma (ICP). For ICP systems, an inductive coil (electrode) is conventionally driven at a high frequency using an RF supply. The inductive coil and RF supply provide a source power, or top power, for plasma generation. In ECR systems, a microwave power source (for example, a magnetron) is used to provide a top power. Both ICP and-ECR systems have a separate power supply known as bias power or bottom power, which may be employed for directing and accelerating ions from the plasma to a substrate assembly or other target. In either case, voltage that forms on a susceptor or chuck (also known as the direct current (DC) bias), is affected by the bottom power (RF bias); whereas, current is affected by the top power.
It has been known that control of particulate contamination is imperative for cost effective, high-yielding manufacture of VLSI circuits. This control is by necessity increasing with increasingly smaller lines, feature sizes and critical dimensions being designed on such circuits. Contamination particles cause incomplete etching of work pieces such as reticules or wafers in spaces between lines, thus leading to an unwanted electrical bridge. Further, contamination particles may induce ionization or trapping centers in gate dielectrics or junctions or in reticule areas which will be used in semiconductor fabrication, leading to electrical failure of a fabricated part.
The major sources of contamination particles are personnel, equipment, and chemicals. For example, people, by shedding of skin flakes, create particles which are easily ionized and can cause defects. It is estimated that particles sized from less than 0.01 micrometers to 200 micrometers and above should be of concern during the processing of semiconductors. xe2x80x9cClean roomsxe2x80x9d are typically used for semiconductor manufacture, and through filtering and other techniques, attempts are made to prevent entry of particles with sizes of 0.03 micrometers and larger. It is virtually impossible, however, to keep particles smaller than 0.03 micrometers out of a clean room.
To address the problem of semiconductor contamination, a Standard Mechanical Interface (SMIF) system was devised. The SMIF system provides a small volume of still, particle-free air, with no internal source of particles, for transporting wafers. SMIF designs are discussed in U.S. Pat. Nos. 5,752,796 (Muka) and 5,607,276 (Muka et al.).
While the SMIF system is useful for preventing particle contamination during transport of the wafers, it is wholly ineffective at preventing contamination during processing of the wafers. The SMIF containers are used during the transport of the wafers, but are removed when the wafers are placed in processing chambers for wafer processing.
Particulate contamination builds up within work piece processing chambers, such as a plasma processing chamber. This build up of contaminants must be cleansed from the processing chambers periodically. This entails considerable time and effort and requires the removal of the processing chamber from a production line. This, in turn, causes lost production time and increases costs.
There is, thus, a need in the industry for a low cost and effective method and apparatus for reducing the need to periodically clean work piece processing chambers, such as a plasma processing chamber.
The present invention provides a removable container which is inserted into a processing chamber and in which the work piece processing is carried out. The container has at least one side and a base, as well as an ingress and egress for the work piece. The container further includes one or more ports located in the side which connect with ports of the processing chamber which provide gasses or other materials used in processing. The container is made of materials allowing the container to have an effective life at least as long as the required processing, preferably allowing the container to be reused a number of times. A locking mechanism may be included to lock the container within the chamber.
The present invention also provides a system for processing a semiconductor work piece. The system includes a processing chamber and a removable container having the characteristics noted in the preceding paragraph. In one aspect of the invention, the processing chamber is a plasma processing chamber.
The present invention further provides a method of processing a semiconductor work piece in which the work piece is provided within a container, the container being removably inserted in a work piece processing chamber, with the processing being accomplished inside the container.
The invention may be used to process any work piece associated with semiconductor fabrication including, but not limited to, reticules, masks, leads, wafers, and packages.